Good stuff Bob...
The BR that you commented out is there for a reason - it helps separate the header from the banner ad (if you ever decide to use that position for banners).
So, remember that you have made the edit because later - if you invoke a banner under the header, you may need to re-instate that BR.
When I comment out bits of code or HTML, I always put an "identifier" in the comment tags, so I know that the edits are mine...
HTML Code:
<!-- GP EDIT BEGIN <br class="clearBoth" /> GP EDIT END -->
Where GP are my initials.
Later, if I need to find my own edits, I just use admin>>>tools>>>developer toolkit to find instances of GP EDIT BEGIN